If frum Jews were all that much into opulence, they would need to maximize income. Studying Torah is a way to minimize income and reduce discretionary spending. Merely being Shomer Shabbos wipes out most of one’s earning potential (denies access to inexpensive high quality university education, reduces most job prospects, forces one to live in only a handful of fairly expensive areas). The truth is that even being “modern Orthodox” with a kippah in the pocket requires great mesiras nefesh.
The generation that survived the holocaust (especially those in Europe, but even those in America could be considered survivors since the war could have gone the other way) often saw living well as the best revenge (but also note that most Jews who were around then do not have frum descendants today).